Broaching tool



H/ T ORNEY C. C. HANSEN BROACHING Toon Filed Jan. 8. 1926 April 3, 1928.

Patented Apr. 3, 1928.

1,664,623 PATENT oFF1cs.

CHARLES c. HANSEN, or EASTON, rENNsnvAmA, AssreNo'nfro rNGnnseLnnANn COMPANY, OF JERSEY CITY, NEW JERSEY, A kCBIORAJPION OF NEW JERSEY.

BROACHING 'rootl Applicationfled January 8, 1926. Serial No. 80,017.

This invention relates to breaching tools,

but more particularly to that type of breach# ing-tools adapted for severing blocks of rock from the mass. l

Usually in such quarrying operations, it `is a common practice to drill a series of holes in line. The adjacent holes are .so spaced with respect to each other that a narrow-,wall of rock remains therebetween and they walls thus formed are afterwards cut away by means of a breaching tool.

One type of broaching tool commonly used for this purpose comprises a rectangular bed portionhavinga cutting face at one en and either a round or hexagonal shank at the other end. -Due to various causes, princi ally to Vthe small cross sectional area of `the shank which this form of construction permits, it has been found exceedngly diflicult to prevent the departure of the cuttingv face of the breach from a desired course.

It is therefore an object of this invention to construct a breaching tool of uniform.A

rigidity throughout its length.

Another object is to provide a large area of contact between the tool and its guide.

Other objects will be in part obvious and in part pointed out hereinafter.

The invention is shown in one of its preferred forms in the accompanying drawings, in which Figure 1 is an elevation of the breaching tool showing the manner in which it is guided by a front head of a. rock drill, only a portion of the front end of the drill being shown for illustrative purposes, i

Figure 2 is an elevation in section taken through Figure 1 on the line 2 2 looking in the direction of. the arrows, and

Figure 3 is a perspective view of the shank end of a breaching tool showing al modification of the invention.

Referring to the drawings, the invention is shown applied to a rock drill, only the front end of the cylinder A being shown. Inserted in the front end of the cylinder A 'is a breaching attachment or front headV B of the type which constitutes the subject matter of my eopending application, Serial No. 68,262, filed November 11, 1925, for a broa-ching attachment for rock drills. The front head B is accordingly provided with a forwardly projecting cylindrical portion C which carries at its forward end an extension D provided on its inner face with a flat cheek plate F. The cheek plate F is preferably somewhat` shorter than the face E so that a. shoulder G is formed at the inner end of said cheek plate.

Secured to one side of the extension D isa guideblock H held in position in this instance by means. of suitable eye-bolts J secured on opposite sides of the extension D. VSince the front head yB is described in detail in'the aforesaid application, rand since it forms no 'part of the present inn ventlon further description thereof 1s Conl sidered unnecessary,other vthan to point out that the cheek plate F and the guide block I-I form a 'guidewa'y K for slidablyguiding j.

a working implement, or more specifically, a breaching tool. x p n In accordance with the practice of the. inven-v tion,V a' breaching tool `L having a body portion L of substantially uniform rectangular cross sectional area of which the rearward f portion forms a shankY is endwvith a T-shaped head is preferably also rectangular and may be, as shown, of somewhat smaller length than the width of .the body portion 'of the broaching provided 'at one kstool, L. The head O in this instance serves as the impact end of the broaching tool for the reception of the blows delivered by a piston P, and which blows in this instance are transmitted to said head by an anvil block Q interposed between said piston and the breaching tool. The head O is preferably 'of sufciently greater depth than the body portion of the broaching tool L so that shoulders R may be formed on the lower side of said head to cooperate with the shoulder G of the cheek plate F and a. shoulder S formed on the guide block H for preventing ejection of the broaching tool L from the front head B by the hammer piston and to prevent removal o f the tool from the front head when vsaid tool is being with-y drawn from the work.

' Although the head O isillustrated in the drawings as having shoulders R on either side thereof, it is to be understood that I do not wish to limit myself to the showing in the drawings, since the invention may be modified in various other forms, such as for instance, a shoulder on only one side of the head O.

In the present instance the broaching tool L is Hared at its other end and is. provided dep art from with a smooth concave cutting face T substantially of the same width as the body portion of said tool. By thus forming the cuttingface-T -in the manner described, said cutting face Vmay eXtend well on opposite sides of a wall of rock U which separates adjacent drill holes V. In this manner a convex cut will be formed on the wall U so that the cuttings may readily drop to the bottom of the .holes V and the breaching tool L may be more `easily supported and held against displacement on the rock face.

Byv means of lthe lpresent invention, a breaching tool may be formed which possesses substantially unifornr strength throughout its length, thus eliminating'the tendency of the breaching tool to creep or well U- c A l In the modiication illustrated in Figure 3 a broaehing tool W is shown in which a head X is provided with a shoulder 'R on only one sidethereof.' The shoulder R in this modiiication may, if desired. be mac e of somewhat greater depth thanth'e shoulders R shownl from the work. With the exception of theV head X the breaching tool W is in all other respects substantially like the breaching tool 7the nari-cwest pointof the shown in the preferred modilication. By forming only one shoulder on the tool W it is obvious that either of the shoulders Gr 0r S of the front head B 0r the guide blockI-IV may be eliminated if desired. i Y

I claim: V L1A breaching tool comprising a flat rec tangular body portion of substantially uniform cross sectional area throughout its length to prevent flexion thereof, a portion of saidv body portion comprising a shank adaptedl to cooperate slidably with a guiding attachment, a' shoulder at one end of Said pol-, tion forming a head adapted to receive the blows of arock drill piston and a cutting bit at the other end of the bodyportion,l Said bit being of substantially the same width Vas body portion.

2. A breaching` tool comprising a'iiat reel form cross sectional area throughout its -length to prevent flexion thereof, opposedshoulders at one end of the body po'rtionand'k `tangular body portion of substantially uni- 'l y V55 head of rectangular cross section for en# gagement with al guidingV attachment and against which head vblows of impact may be delivered. and a cutting bit at theotherend o f and of the samewidthl as the body por,-v t-ion. f

' In testimony whereof I have signed this specification. 

